It is required in some rotary clutches that the clutch has no play in its closed state and that the clutch flanges are brought back together in the same angular position after the release and after any relative rotation which may have occurred in the released state. An example of this are the rotary clutches which are positioned between a motor drive and a driven member to be moved and precisely set, e.g., a slide. Too much play between the drive and the driven member would in such an instance adversely affect the adjustment accuracy and cause a constant instability in the regulating circuit. A clutch is necessary between the drive and the driven member in order to make manual operation possible, e.g., if the drive energy stops or if maintenance is performed on the driven member. It can be necessary, considering the regulating tasks in the engaged state, that certain geometric relationships are constantly assured between the drive and the driven member. Known clutches of this type are very expensive on account of the requirements of great precision placed on the specially shaped individual parts; however, the aim striven for is never quite satisfactorily reached.
The invention therefore has the task of creating a rotary clutch of the type initially mentioned which is inexpensive to construct, without play and which assures a predetermined angular position of the clutch parts in relation to each other even after a relative rotation of the clutch parts in the disengaged state after reengagement.